Control method and apparatus for pressure, vacuum or pressure-vacuum circulation in drilling system

ABSTRACT

A drill system uses double walled concentric pipe and a drill bit attached at one end of the drill pipe and a power swivel at its upper end having means for applying compressed air to the outer annulus within the drill pipe and means for attaching a vacuum line to the center annulus of the drill pipe. A flexible hose attached to the vacuum portion of the drill pipe has an inductor assembly using compressed air to create a vacuum to remove the cuttings during the drilling operation. A diverting valve, having its input connected to pressurized air from an air compressor, has one output connected to the input of the inductor and its other output connected to the outer annulus portion of the drill pipe. The diverter valve provides the operator the ability to pressure reverse circulate, to vacuum reverse circulate, or an infinitely variable combination of the two.

[4 Nov. 18, 1975 [54] CONTROL METHOD AND APPARATUS 1 FOR PRESSURE, VACUUM OR PRESSURE-VACUUM CIRCULATION IN DRILLING SYSTEM [75] Inventors: Robert W. McQueen; Robert W. Ruhe, Jr., both of Houston, Tex.

. [73] Assignee: Dresser Industries, Inc., Dallas, Tex.

22 Filed: Feb. 26, 1975 21 Appl. No.: 553,415

Primary Examiner-David H. Brown Attorney, Agent, or FirmWi1liam E. Johnson, Jr.

[57] 1 ABSTRACT A drill system uses double walled concentric pipe and a drill bit attached at one end of the drill pipe and a power swivel at its upper end having means for applying compressed air to the outer annulus within the drill pipe and means for attaching a vacuum line to the center annulus of the drill pipe. A flexible hose attached to the vacuum portion of the drill pipe has an inductor assembly using compressed air to create a vacuum to remove the cuttings during the drilling op- 5 Claims, 2 Drawing Figures [52] US. Cl. 175/60; 175/71; 175/209; 175/215 [51] Int. C13... E21B 7/00; E21C 7/02; E21B 21/00 [58] Field of Search 175/60, 71, 207, 209-218 [56] g I References Cited UNITED STATES PATENTS 1,985,157 12/1934 Friedman et a1 175/209 X 1,993,642 3/1935 Aarts et a1. 175/210 X 2,041,690 5/1936 Baumeister et a1. ..-175/209 X 2,849,213 8/1958 Failing 175/215 X 3,057,417 10/1962 Sandvig 175/213 X 3,807,514 4/1974 Murrell 175/212 X FOREIGN PATENTS OR APPLICATIONS 1,086,534 10/1967 United Kingdom 175/215 I AIR COMPRESSOR 5| J US. Patent Nov. 18, 1975 Sheet 1 012 3,920,090

,. 1 I L I Uv 1 11' s%u \w4 I 4 AIR 13 COMPRESSOR 5| v u 24 "2352 2s 3 US. Patent 0 Nov. 18,1975 SheetZ 0f2 3,920,090

1 [BACKGROUND OF THE INVENTION This invention relates generally to the art of drilling a hole in the earths surface using air as a circulation medium, and specifically to method and apparatus for varying between a pressurized system, a vacuum system and an infinite numberof combinations of pressure and vacuum in drilling a hole in the earth formations.

his well known in the prior art to use air as a drilling fluid for circulating'the drill cuttings to the earths surface. It has also been known in the art to employ a vacuum system for removing the drill cuttings-in lieu of using pressurized air; However, to the Applicants knowledge, there have been no prior art systems presented= which contemplate the controlled combination of a vacuum system and a pressurized air system to enhance the removal of the drill cuttings in accordance with the present invention. t

It is therefore the primary object of the present invention to provide new and improved method and apparatus for using air as a circulation medium in a drilling system;

It is also the object of the present invention to provide new and improved method and apparatus for providing an optimized balance between the pressurized air and the vacuum used in a well drilling apparatus;

It is yet another object of the present invention to provide a new and improved method and apparatus for simplifying the ease of switching between pressurized air, vacuum, and pressure-vacuum circulation systems indrilling operations. k

"The objects of the invention are accomplished, in general, by a method and apparatus which utilize a common source of compressed air to provide both the compressed air portion and the'vacuum portion of a common drilling system and a diverter valve interspersed therebetween to provide various combinations of compressed air and vacuum as the circulation fluid in adrilling system. 7

2 These and other objects, features and advantages of the present invention will be more readily appreciated from areadirig of thefollowing detailed description and drawing, in which: I

FIG. 1 is an elevated view, partly in cross section, of the drilling system according to the present invention;

and t FIG. 2 is a diagrammatic view, partly in cross section, illustrating the circulation swivel and drill bit-attached to the double walleddrill pipe according to the present invention. f 7

Referring now to the drawing in more detail, especially to FIG. 1, ari'earth boringmachine generally des-. ignated by the reference number 12 is shown positioned at a drill site. The earth boring machine l2 includes a derrick 8 that provides a support frame. A

traveling power head or traveling frame 3 is mounted for travel along the derrick 8. A, drill string unit 10 is connected to the traveling; power head 3. The drill string 10, shown in more. detail in FIG. 2, is comprised ofdouble walled, concentric tube drillpipe. for example, as is shown in U.S. Pat. No. 3,208,539 to H. I. Henderson.

A swivel 11,- shown in more detail in FIG. 2, is connected to the-top part of the drill string and in turn is attached; to awflexible hose 13 which passes over a support wheel 1 which is suspended from a pair of sheaves 5 and 6 attached to the derrick 8. The radius of the sup-- port wheel 1 substantially matches the bend radius of the hose 13.. This provides smooth radius for flow of drill cuttings through the hose 13. The support wheel 1 is rotatably mounted upon anaxle 14'. The axle 11 is connected by means of a connecting line 4 to the sheaves 5 and 6. The connecting line 4 is also attached to -.a counterbalance weight 7. The counterbalance weight 7 provides a counterbalance force substantially equal to the weight of the hose l3.

The flexible hose 13 is connected at its other end to a conventional inductor device generally designated by the reference number 15, such devices being well known in the art, for example, as shown in the U.S. Pat. No. 3,031,127 to R. A. Duhaime et al. The lower end of the inductor device 15 is connected to a stand pipe 9 by means of aclamp 16 to the derrick 8.

An air compressor 21 has its output line 22 connected to the input 23 of a diverting valve which is generally indicated by the reference numeral 24. One of the output lines of the diverting valve 24 is connected by the air line 25 to the motivatingair input 26 of the inductor device 15. The other output of the diverting valve 24 is connected by air line 27, preferably being a flexible hose, to the input 28 of the swivel 11. The diverting'valve 24 includes a rotor 29 which is rotatable by an operator to control whether air passes .through the lines 25 or 27 and the extent of such passage.

. Air pressure valves 51 and 52 are located in air lines 27 and 25, respectively. 1

Referring now to FIG. 2, the swivel 11 is shown in greater detail. The swivel ll includes a housing 31 which surrounds the double walled drill pipe 10 and which is adapted to remain stationary with respect to the traveling power head 3 (shown in FIG. I) and which allows the drill pipe 10 to rotate therein. A pair of packing elements 32 and 33 are provided to seal off the compressed air which enters input port 28 and thus prevent leakage of the compressed air from the interior of the housing 31. A plurality of ports, shown as ports 34 and 35, are located between the packing rings 32 and 33 in the outer wall 36 of the concentric drill pipe assembly 10. The ports 34 and 35 thus provide a means for the compressed air which enters at input port 28 to pass from the interior of the housing 31 to the annulus 39 betweenthe outer drill pipe wall 36 and the inner drill pipe wall 37.

Adrill bit assembly, shown generally by the reference numeral 38, is attached to .the lower end of the drill string assembly 10.'The drill bit assembly 38 can be of various designs well known to those skilled in the art which allow communication between the outer annulus 39 and the boreholeand also between the borehole and the inner annulus 40 through which the drill cuttings are returned tothe earths surface. If desired, the drill bit 38 can be constructed in accordance with the teachings of U.S. Pat. No. 3,208,539 to H. I. Henderson.

A packer assembly 42 is positioned between the exterior of the drill pipe assembly and the wall 43 of the borehole for purposes as explained hereinafter.

Referring now to the operation of the apparatus according to FIG.s l and 2, it should be appreciated that unless the packer 42 shown in FIG. 2 provides a good seal between the drill string 10 and the wall 43 of the borehole, the introduction of compressed air into the annulus 39 is very likely to cause the drill cuttings 41 to go past the packer 42 instead of up through the center annulus 40 of the drill pipe. The Applicant has sometimes experienced difficulty in providing a good seal by the use of the packer 42, especially when drilling under arctic conditions through regions of permafrost and in other unconsolidated formations.

The Applicant has discovered, however, that by maintaining the vacuum within the center annulus 40 stronger or greater than the compressed air in the annulus 39, based on a per unit volume, the drill cuttings 41 will pass up through the annulus 40 rather than escaping past the packer seal 42.

The drilling of a hole begins with the traveling power head 3 near the top of the derrick 8. The drill string is rotated and the drill bit at the bottom of the drill string 10 disintegrates the earth formations to form the desired borehole. As the borehole penetrates deeper into the earth, the traveling power head 3 moves downward. As the compressed air and/or vacuum causes the drill cuttings to pass up through the center passage 40, the cuttings and debris from the earth borehole pass up through the flexible hose 13 into the inductor device and out through the curved stand pipe 9 either onto the surface of the earth or into a collection'vehicle. The support wheel 1 supports the connecting hose 13. As the traveling power head 3 moves downward, the support wheel 1 rotates on the axis 14 insuring that a smooth radius of connecting hose will be maintained. The counterbalance 7 provides a lifting force on the support wheel 1 maintaining a slight tension in both ends of the connecting hose 13. The connecting hose 13 is maintained in a vertical position as the traveling power head 3 moves in the derrick 8.

As shown in FIG. 1, the rotation of the rotor 29 by the drilling operator controls the amount of air which passes to the swivel 11 and also to the inductor device 15. The valve 51 in the air line 27 passing to the swivel l1 and the valve 52 in the air line passing to the inductor device 15 provide a means for monitoring an allowing the control of the compressed air which is put into the annulus 39 and the vacuum which is created in the center annulus 40. Based upon calibration charts, the valve 52 which is indicative of compressed air in the line 25 is easily correlated to the vacuum created by the inductor device 25. Thus, as the drill stem 10 and drill bit 38 are rotated into the earths surface in drilling a hole, the operator adjusts the rotor 29 to create the desired combination of pressurized air and vacuum to enhance the drilling operation. The Applicant has also discovered that, depending upon the formations being drilled, it is sometimes better to use only pressurized air and other times better to use only the vacuum. In such instances, the rotor 29 is rotated one way or the other to create the desired effect. It should also be appreciated that another means of determining when the vacuum is exceeding the compressed air is determined by whether the drill cuttings are attempting to leak past the packer 42 or, alternatively, if the packer 42 is not used, when drill cuttings are blowing out of the borehole around the exterior of the drill pipe assembly 10.

Thus it should be appreciated that there have been described herein the preferred embodiments of the present invention wherein various methods and apparatus are described relating to the control ofa drilling system which allows the switching of the circulation system from vacuum to pressurized air and various combinations of vacuum-pressure circulation. However, those skilled in the art will recognizethat modifications of the preferred embodiments will be obvious from a reading of the foregoing detailed specification. For example, while the preferred embodiment contemplates the use of double walled, concentric tube drill pipe, the invention also contemplates the use of single wall drill pipe which enables compressed air to pass down through the annulus external to the drill pipe to the bottom of the borehole and for the vacuum to be induced within the center passage traveling back up through the drill pipe. Furthermore, those skilled in the art will recognize that although the preferred embodiment contemplates the use ofa rotary drilling system, the system is equally applicable to percussion type drill strings and drill bits which do not require that the drill string and drill bit be rotated. It should also be appreciated that, although not illustrated, means can be provided for insuring that the vacuum created within the center passage always exceeds the amount of the pressurized air by using appropriate stops and other controls in the diverter valve which is used to divert the air from the compressor to the pressurized air and vacuum creating means.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

l. A system for drilling a hole in earth formations, comprising:

a string of drill pipe having a center longitudinal passage;

a drill bit attached to the lower end of said string of drill pipe;

means to introduce pressurized air into the bottom of the hole being drilled;

means to create a vacuum through said center passage of said string of drill pipe for circulating the drill cuttings from the bottom of the hole being drilled; and

means for simultaneously varying said means to introduce pressurized air and said means for creating a vacuum, said simultaneously varying means comprising a diverter valve for diverting a common source of pressurized air between said means to introduce pressurized air and said means to create a vacuum.

2. The system according to claim 1 wherein said simultaneously varying means comprises means for increasing the amount of pressurized air introduced into the bottom of said drilled hole while decreasing the magnitude of the created vacuum.

3. The system according to claim 1 wherein said simultaneously varying means comprises means for decreasing the amount of pressurized air introduced into the bottom of said drilled hole while increasing the magnitude of the created vacuum.

4. A method of drilling a hole in earth formations, comprising:

rotating a string of drill pipe having a center longitudinal passage and a drill bit into said earth formation;

causing pressurized air to be introduced into the bottom of said drilled hole; creating a vacuum in the said center longitudinal passage of said string of drill pipe; and

simultaneously increasing the amount of said pressurized air and decreasing the magnitude of said vacuum.

6 creating a vacuum in the said center longitudinal passage of said string of drill pipe; and simultaneously decreasing the amount of said pressurized air and increasing the magnitude of said vacuum. 

1. A system for drilling a hole in earth formations, comprising: a string of drill pipe having a center longitudinal passage; a drill bit attached to the lower end of said string of drill pipe; means to introduce pressurized air into the bottom of the hole being drilled; means to create a vacuum through said center passage of said string of drill pipe for circulating the drill cuttings from the bottom of the hole being drilled; and means for simultaneously varying said means to introduce pressurized air and said means for creating a vacuum, said simultaneously varying means comprising a diverter valve for diverting a common source of pressurized air between said means to introduce pressurized air and said means to create a vacuum.
 2. The system according to claim 1 wherein said simultaneously varying means comprises means for increasing the amount of pressurized air introduced into the bottom of said drilled hole while decreasing the magnitude of the created vacuum.
 3. The system according to claim 1 wherein said simultaneously varying means comprises means for decreasing the amount of pressurized air introduced into the bottom of said drilled hole while increasing the magnitude of the created vacuum.
 4. A method of drilling a hole in earth formations, comprising: rotating a string of drill pipe having a center longitudinal passage and a drill bit into said earth formation; causing pressurized air to be introduced into the bottom of said drilled hole; creating a vacuum in the said center longitudinal passage of said string of drill pipe; and simultaneously increasing the amount of said pressurized air and decreasing the magnitude of said vacuum.
 5. A method of drilling a hole in earth formations, comprising: rotating a string of drill pipe having a center longitudinal passage and a drill bit into said earth formation; causing pressurized air to be introduced into the bottom of said drilled hole; creating a vacuum in the said center longitudinal passage of said string of drill pipe; and simultaneously decreasing the amount of said pressurized air and increasing the magnitude of said vacuum. 